The present invention relates to a printing system using a power-saving printing method, and more particularly to a power-saving printing method of a printing system comprised of a computer providing information and an image-forming device connected thereto. The power-saving printing method activates the image-forming device prior to a print operation in order to reduce an extended print time resulting from a warm-up period of the image-forming device.
Recently, an energy star computer program sponsored by the U.S. Environmental Protection Agency (EPA) allows manufacturers of energy efficient office equipment complying with specified contractual terms and conditions to use a designated energy star logo indicating the energy efficiency of their product. The energy star computer program is a cooperative effort between the U.S. Environmental Protection Agency and computer device manufacturers to promote the production and sale of energy efficient office equipment. The program is particularly aimed at reducing air pollution resulting from the generation of power necessary to operate currently available office equipment. Accordingly, the program encourages the production of office equipment having power-saving features. Such equipment consumes less power, and thus helps reduce the production of air pollution.
To reduce power consumption, many devices, for example electrophotographic printers, are equipped with operational controllers for placing the device into a power-saving mode during periods of non-use. With electrophotographic printers, however, withdrawal of the device from the power-saving mode, upon entry of a print code can cause a user to experience an inconvenient delay before printing actually commences because the device requires a warm-up period. The problem of not knowing how long a warm-up period will last has long plagued the art as evidenced by the recently issued U.S. Pat. No. 5,293,463 entitled Image Processing Apparatus issued on 8 Mar. 1994 to Masuda. This art provides an image processing apparatus adapted to inform a user of the time required to elapse before an image forming command can actually be executed, thereby attempting to eliminate user anxiety that might otherwise occur. Although such art keeps the user informed of the required time delay, it is our experience that most users demand more. That is, we have observed that users don't just want to know how long their inconvenience will last, rather they desire more efficient office equipment that, in fact, actually exhibits a reduction in delay time when operated under the same conditions.
Another recent effort directed towards power conservation is disclosed in U.S. Pat. No. 5,218,704 entitled Real-Time Power Conservation For Portable Computers issued on 8 Jun. 1993 to Watts, Jr. et al. Here, a portable computer employs a monitor to determine whether a CPU may rest based upon a real-time sampling of the CPU activity level. If the monitor determines the CPU may rest, a hardware selector reduces CPU clock time; if the CPU is to be active, the hardware selector returns the CPU to its previous high speed clock level. Since the CPU switches back into full operation from its rest state without any user input or request, we question whether there is any significant reduction in the amount of power consumption that actually results from this application.